# from collections import deque
# queue = deque(['a','b','c'])
# queue.append('d')
# print(queue)
# queue.append('e')
# print(queue)
# print(queue.popleft())
# queue.popleft()
# print(queue)
# new_queue = deque(['f','g'])
# queue.extend(new_queue)
# print(queue)